Every floor scrubber gets a score from 0 to 100% built from six factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Scrubbers are grouped by cleaning path, under 17 in and 17 in and up, and use the same scale in both groups.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per inch of cleaning path | 30% |
| Cleaning path | width scrubbed in one pass | 20% |
| Recovery tank | dirty-water tank size, which sets how far it goes between dumps | 15% |
| Runtime | battery run time per charge; corded machines score the middle | 15% |
| Noise | sound level at the operator | 5% |
| Warranty | parts warranty on the machine | 15% |
Where the numbers come from
Cleaning path, tank sizes, runtime, sound level, weight and warranty come from the maker’s brochure, spec sheet, manual or product page, or the maker’s own copy on a retail listing. Warranty terms come from the maker’s published warranty statement where there is one. Where a maker’s figures conflict, the product page notes both and the score uses the more conservative one. Prices are checked at Amazon, and the lowest price at a store the page links to is used.
The factors
Value is the current price divided by the cleaning path, in dollars per inch, on a log scale, so halving the price always counts the same. $400 per inch scores zero and $60 per inch full marks.
Cleaning path is the width scrubbed in one pass, which sets how quickly a machine covers a floor: 11 in scores zero and 24 in full marks.
Recovery tank is the size of the dirty-water tank, which sets how far a machine goes before it has to be emptied, on a log scale: 1 gal scores zero and 15 gal full marks.
Runtime is the battery run time per charge the maker states: 30 minutes scores zero and 4 hours full marks. Where a maker gives a range, the low end is used. A corded machine has no battery to run down but can only reach as far as its cord, so it scores the middle of the scale.
Noise is the sound level at the operator: 75 dB(A) scores zero and 60 dB(A) full marks. Quieter machines can clean while a store, office or hospital is open.
Warranty is the maker’s parts warranty on the machine: 1 year scores zero and 5 years full marks. Where a warranty covers the battery and the motor for different terms, the shorter term is used. Labor coverage is shown on the product page but not scored.
What isn’t scored
Productivity in square feet per hour is listed but not scored. It is a theoretical figure, path width times an assumed walking speed, and makers work it out on different bases, so two machines with the same path can claim figures several times apart. Squeegee width, solution tank size, brush type and speed, brush pressure, battery type, voltage, cord length, weight, labor warranty and release date are listed but not scored.
Missing data
If a recovery tank size or sound level isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. Battery runtime is treated differently, because it is the figure that most separates one battery machine from another: a battery machine whose maker doesn’t publish a runtime scores zero for runtime, marked estimated, so a listing that leaves it out can’t rank on a free middle score. The same applies to a missing cleaning path. Warranty works the same way: a maker that doesn’t publish one gets no warranty counted, so that factor scores zero, the same as a one-year warranty, and is marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.